When an internal prosthesis bears on an osseous body or is inserted between several osseous bodies, the position of this prosthesis is often maintained in place by reliefs or irregularities of protruding form on one face of this prosthesis and acting as anchor in the surface of this osseous body.
In the case of intervertebral prostheses, in particular functionally replacing an intervertebral disc, this maintenance can be ensured in several ways. One possibility consists of providing pins extending beyond the surface of the prosthesis, these pins being encrusted, or impacted, in the surface of the vertebral disc, under the effect of the pressure exerted by the vertebrae surrounding the prosthesis.
The length of these impacting pins in nonetheless limited by the fact that the two vertebrae must be sufficiently separated to enable insertion of the prostheses and pins in the space thus obtained.
For obtaining greater anchoring depth, it is known from patent FR 2 659 226 how to use a prosthesis with one or several projections fixed in winged form, extending beyond the plates in contact with the vertebrae and oriented along a plane parallel to the sagittal plane of the rachis. The surgeon then begins by boring a trench in the surface of the vertebral disc opening into one of the sides of the body of the vertebra. This trench is made using a bone chisel or osteotome, and opens towards the outside in a direction corresponding to the direction in which the prosthesis and its winglet will be inserted.
Because of the position of the winglets parallel to the sagittal plane, and given that the prosthesis does not have a rotary shape and must be oriented in a precise angular position around the rachis axis, the prosthesis must therefore be inserted according, to a path allowing median access during the intervention, therefore usually an anterior path.